Bioinsecticides against insect pests

Trees have finally found an ally in the fight against insect pests.ZoomZoom
© Claude Guertin - INRS-Institut Armand-Frappier

Article published in theCourrier Laval on June 4, 2006.

How many of you believe that biopesticides are an invention of the 20th Century??

Ask your grandparents how they would protect their crops from aphids. Without hesitating, they will answer: "with ladybugs!"

Although it has existed as long as man has been growing plants, with the use of chemical products, knowledge about biological control was lost. Because these products are not without effects on human health, a return to more natural methods is under way. Birds, insects, soaps, all these biological products can be put to good use in this battle!

"The use of biological agents to fight against pests is older than we think" says Dr. Guertin, researcher at the INRS-Institut Armand Frappier. Since 1992, Dr. Guertin and his team have specialized in the development of bioinsecticides, i.e., biopesticides directed against insect pests. Useful in helping to avoid insect epidemics such as grasshoppers or mosquitoes and in reducing the risks associated with too many birds near airports, bioinsecticides allow us to treat natural forests, as well as agricultural and aquatic milieux. Spreading microorganisms such as viruses or bacteria, Bacillus thuringiensis (Bt) for example, causes illness in the insect that ingests the biological agents. But what can we do about insects that do not eat, bite directly into the leaves, or hide under the bark? The micro-fungi Beauveria bassiana can solve all these problems. It is deposited on the insect’s shell and infiltrates the organism bit by bit. This contact is fatal.

"Fall is a nice time of the year to collect field samples.", says Dr. Guertin. Researchers who collect sick insects identify the microorganisms responsible for these infections. These pathogens, identified in their natural milieu and brought back to the laboratory, constitute a bank of potential bioinsecticides. They are tested under controlled conditions to determine their specificity. Before going to war, we must know the enemy: when he appears, and his interaction with the plant. It is also important to evaluate the impact of external factors on the microorganism such as harmful UV radiation or the rain washing off the deposits. Once they are armed, the bioinsecticides are released in great number in the environment to enter into combat against the pests.

The development of such products takes a long time. Although biological control is gaining ground, North America remains fond of using chemical products. Old Europe and its agriculture are way ahead of us!